Snap-fit lens barrel systems and methods

ABSTRACT

Techniques for facilitating wide field of view (FOV) imaging systems and methods are provided. In one example, an imaging device includes a lens barrel. The lens barrel includes a first body portion including a first lens element at least partially disposed therein, a second body portion including a second lens element and a third lens element at least partially disposed therein, and a snap-fit mechanism. The first, second, and third lens elements include a lens system configured to pass electromagnetic radiation from a scene to an image capture component. The snap-fit mechanism includes a plurality of finger members extended from the first body portion and a plurality of complementary notches in the second body portion. The finger members are configured to engage with the notches to releasably secure the first body portion to the second body portion. Related methods and systems are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 63/269,197 filed Mar. 11, 2022 and entitled“SNAP-FIT LENS BARREL SYSTEMS AND METHODS,” which is incorporated hereinby reference in its entirety.

TECHNICAL FIELD

One or more embodiments relate generally to optical components and moreparticularly, for example, to wide field of view imaging systems andmethods.

BACKGROUND

Imaging systems may include an array of detectors arranged in rows andcolumns, with each detector functioning as a pixel to produce a portionof a two-dimensional image. For example, an individual detector of thearray of detectors captures an associated pixel value. There are a widevariety of image detectors, such as visible-light image detectors,infrared image detectors, or other types of image detectors that may beprovided in an image detector array for capturing an image. As anexample, a plurality of sensors may be provided in an image detectorarray to detect electromagnetic (EM) radiation at desired wavelengths.In some cases, such as for infrared imaging, readout of image datacaptured by the detectors may be performed in a time-multiplexed mannerby a readout integrated circuit (ROIC). The image data that is read outmay be communicated to other circuitry, such as for processing, storage,and/or display. In some cases, a combination of a detector array and anROIC may be referred to as a focal plane array (FPA). Advances inprocess technology for FPAs and image processing have led to increasedcapabilities and sophistication of resulting imaging systems.

SUMMARY

In one or more embodiments, an imaging device includes a lens barrel.The lens barrel includes a first body portion, a second body portion,and a snap-fit mechanism. The first body portion includes a first lenselement at least partially disposed therein. The second body portionincludes a second lens element and a third lens element at leastpartially disposed therein. The first, second, and third lens elementsinclude a lens system configured to pass electromagnetic radiation froma scene to an image capture component. The snap-fit mechanism includes aplurality of finger members extended from the first body portion and aplurality of complementary notches in the second body portion. Thefinger members are configured to engage with the notches to releasablysecure the first body portion to the second body portion.

In one or more embodiments, a method of manufacturing the imaging deviceincludes disposing the first lens element at least partially within thefirst body portion. The method further includes disposing the secondlens element and the third lens element at least partially within thesecond body portion. The method further includes coupling the secondbody portion to a housing. The method further includes performing acalibration of the second lens element and the third lens element. Themethod further includes coupling, after the calibration, the first bodyportion to the second body portion.

In one or more embodiments, a method of manufacturing the imaging deviceincludes performing a first manufacturing operation when the first bodyportion and the second body portion are connected. The method furtherincludes disconnecting the snap-fit mechanism to separate the first bodyportion from the second body portion. The method further includesperforming a second manufacturing operation when the first body portionis separated from the second body portion.

In one or more embodiments, a method includes providing a lens barrel.The lens barrel includes a first body portion including a first lenselement at least partially disposed therein. The lens barrel includes asecond body portion including a second lens element and a third lenselement at least partially disposed therein. The first, second, andthird lens elements include a lens system configured to passelectromagnetic radiation from a scene to an image capture component.The lens barrel includes a snap-fit mechanism to secure the first bodyportion to the second body portion. The snap-fit mechanism includes aplurality of finger members extend from the first body portion and aplurality of complementary notches in the second body portion. Themethod further includes securing the first body portion to the secondbody portion using the snap-fit mechanism. The finger members areconfigured to engage with the notches to releasably secure the firstbody portion to the second body portion.

The scope of the present disclosure is defined by the claims, which areincorporated into this section by reference. A more completeunderstanding of embodiments of the present disclosure will be affordedto those skilled in the art, as well as a realization of additionaladvantages thereof, by a consideration of the following detaileddescription of one or more embodiments. Reference will be made to theappended sheets of drawings that will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an imaging device in accordancewith one or more embodiments of the present disclosure.

FIG. 2 illustrates a perspective view of an imaging device in accordancewith one or more embodiments of the present disclosure.

FIG. 3 illustrates a cross-sectional view of an optical system inaccordance with one or more embodiments of the present disclosure.

FIG. 4 illustrates a field of view associated with the optical system ofFIG. 3 in accordance with one or more embodiments of the presentdisclosure.

FIG. 5 illustrates a field of view associated with a rear lens group ofthe optical system of FIG. 3 in accordance with one or more embodimentsof the present disclosure.

FIG. 6 illustrates a graph with a relative illumination curve associatedwith a lens system including a front lens group and a rear lens groupand a relative illumination curve associated with just the rear lensgroup in accordance with one or more embodiments of the presentdisclosure.

FIG. 7A illustrates a graph showing a modulation transfer function inrelation to radii associated with surfaces of a lens element inaccordance with one or more embodiments of the present disclosure.

FIG. 7B illustrates a graph showing a modulation transfer function inrelation to a thickness of a lens element and a distance between twogroups of lenses in accordance with one or more embodiments of thepresent disclosure.

FIG. 7C illustrates a graph showing a relative illumination in relationto a thickness of a lens element and a distance between two groups oflenses in accordance with one or more embodiments of the presentdisclosure.

FIG. 7D illustrates a graph showing a field of view in relation to radiiassociated with surfaces of a lens element in accordance with one ormore embodiments of the present disclosure.

FIG. 7E illustrates a graph showing a field of view in relation to athickness of a lens element and a distance between two groups of lensesin accordance with one or more embodiments of the present disclosure.

FIG. 7F illustrates a graph showing a relative illumination in relationto radii associated with surfaces of a lens element in accordance withone or more embodiments of the present disclosure.

FIG. 8 illustrates a cross-sectional view of an imaging device inaccordance with one or more embodiments of the present disclosure.

FIG. 9 illustrates a flow diagram of an example process formanufacturing the imaging device of FIG. 8 in accordance with one ormore embodiments of the disclosure.

FIGS. 10A, 10B, 10C, and 10D illustrate perspective views associatedwith manufacturing the imaging device of FIG. 8 in accordance with oneor more embodiments of the present disclosure.

FIG. 11 illustrates a flow diagram of an example process for using theimaging device of FIG. 8 in accordance with one or more embodiments ofthe present disclosure.

FIG. 12 illustrates a cross-sectional view of an optical system with twofront lens elements in accordance with one or more embodiments of thepresent disclosure.

FIG. 13 illustrates a cross-sectional view of an optical system withthree rear lens elements in accordance with one or more embodiments ofthe present disclosure.

FIG. 14 illustrates a block diagram of an example imaging system inaccordance with one or more embodiments of the present disclosure.

FIG. 15 illustrates a block diagram of an example image sensor assemblyin accordance with one or more embodiments of the present disclosure.

FIG. 16 illustrates a perspective view of an additional imaging devicein accordance with one or more embodiments of the present disclosure.

FIG. 17 illustrates a cross-sectional view of an upper lens assembly ofthe imaging device of FIG. 16 in accordance with one or more embodimentsof the present disclosure.

FIG. 18 illustrates a cross-sectional view of a lower lens assembly ofthe imaging device of FIG. 16 in accordance with one or more embodimentsof the present disclosure.

FIG. 19 illustrates a flow diagram of an example process formanufacturing the imaging device of FIG. 16 in accordance with one ormore embodiments of the disclosure.

Embodiments of the present disclosure and their advantages are bestunderstood by referring to the detailed description that follows. It isnoted that sizes of various components and distances between thesecomponents are not drawn to scale in the figures. It should beappreciated that like reference numerals are used to identify likeelements illustrated in one or more of the figures.

DETAILED DESCRIPTION

The detailed description set forth below is intended as a description ofvarious configurations of the subject technology and is not intended torepresent the only configurations in which the subject technology can bepracticed. The appended drawings are incorporated herein and constitutea part of the detailed description. The detailed description includesspecific details for the purpose of providing a thorough understandingof the subject technology. However, it will be clear and apparent tothose skilled in the art that the subject technology is not limited tothe specific details set forth herein and may be practiced using one ormore embodiments. In one or more instances, structures and componentsare shown in block diagram form in order to avoid obscuring the conceptsof the subject technology. One or more embodiments of the subjectdisclosure are illustrated by and/or described in connection with one ormore figures and are set forth in the claims.

In one or more embodiments, wide field of view imaging systems andmethods are provided. In some aspects, such systems and methods may beused for infrared imaging, such as thermal infrared imaging. In oneembodiment, an imaging device includes a detector array, an opticalelement(s) to direct electromagnetic radiation associated with a sceneto the detector array, and a lens barrel within which to dispose andhold/secure the optical element(s). The imaging device may include ahousing coupled to the lens barrel. The housing may include (e.g.,enclose) the detector array. In some cases, the housing may include alogic device to process image data from the detector array, memory tostore raw image data and/or processed image data, a battery, and/orother components to facilitate operation of the imaging device. By wayof non-limiting examples, an optical element may include a lens element,a window, a mirror, a beamsplitter, a beam coupler, and/or othercomponent. In an aspect, the imaging device includes a lens systemincluding a front lens group (e.g., also referred to as a front focusinggroup) and a rear lens group (e.g., also referred to as a rear focusinggroup). In some cases, the imaging device may also include other opticalelements upstream of the lens elements, downstream of the lens elements,and/or interspersed between two lens elements.

The detector array may receive electromagnetic radiation directed (e.g.,projected, transmitted) by the lens element(s) onto the detector array.In this regard, the electromagnetic radiation may be considered imagedata. The detector array may generate an image based on theelectromagnetic radiation. The lens element(s) and/or other opticalelement(s) of the imaging device may be transmissive of electromagneticradiation within a waveband dependent on a desired application. In anaspect, the imaging device may be an infrared imaging device forfacilitating capture of a waveband encompassing at least a portion ofthe thermal infrared spectrum, such as a long-wave infrared (LWIR)spectrum. In infrared imaging applications, the detector array mayinclude an array of microbolometers and/or an array of other types ofinfrared detectors. As non-limiting examples, a lens element may includesilicon, germanium, chalcogenide glass (e.g., As₄₀Se₆₀), germaniumarsenide selenium (GeAsSe), Ge₂₂As₂₀Se₅₈, Ge₃₃As₁₂Se₅, zinc selenide,organic material such as polyethylene and 4-methylpentene-1-based olefincopolymer (TPX), and/or generally any lens material appropriate forinfrared applications. Lens material used to manufacture the lenselement(s), respectively, are generally based on a desired application.For example, lens material may be selected to allow a desiredtransmission waveband of the lens elements.

In some embodiments, a wide field of view imaging device, such as anultra-wide field of view (UWFOV), may include lens elements formed usingwafer level optics (WLO) manufacturing processes. In some aspects, theimaging device may be an LWIR camera. As a non-limiting range, an UWFOVimaging device may provide a field of view (FOV) between around 110° andaround 220° (e.g., around 120° and around 160° in some cases). In thisregard, in some cases, a lens system of the imaging device may bedesigned to provide an FOV that exceeds 180° to allow the imaging deviceto capture scene data (e.g., image data in the form of electromagneticradiation) behind the imaging device.

WLO manufacturing processes, such as polymer formation on a substratefollowed by a transfer etch, are generally associated with lower coststhan other manufacturing processes and thus having the option to use, inan imaging device, lens elements formed using WLO manufacturingprocesses allows for cost savings. Lens elements formed as part of awafer-level procedure may then be singulated to obtain individual lenselements that can be disposed in imaging devices. Lens shapes used inUWFOV applications generally lie outside of WLO manufacturing designrules. In this regard, WLO processes impose limitations on lens shapesthat can be produced. As typical examples of WLO manufacturing designrules, a maximum lens sag should not exceed 0.3 mm and a maximum slopealong the curvature should not exceed around 15° or 16°.

To provide ultra-wide FOV imaging capabilities, the imaging deviceincludes a front lens group and a rear lens group, where each lens groupincludes one or more lens elements. The rear lens group may beformed/produced using WLO processes (e.g., due to their lower costsrelative to other manufacturing processes). As such, the lens element(s)of the rear lens group is designed to meet the rules associated with WLOmanufacturing and thus has lower sag and lower slope. In some cases, thelens element(s) of the rear lens group is an aspherical lens element(s).The front lens group may be formed/produced using grinding processes,polishing processes, diamond turning processes, and/or moldingprocesses. In some aspects, both curvatures of a lens element(s) of thefront lens group may be designed to be spherical. The curvatures may beproduced using grinding/polishing processes to provide a double-sidepolished spherical lens element. In such aspects, leveraging thespherical shape of the spherical lens elements, the spherical lenselement(s) of the front lens group may be formed/produced withgrinding/polishing processes, which are generally less expensive thandiamond point turning or molding processes. As such, cost effectiveprocesses may be used to form the front lens group and/or the rear lensgroup dependent on application.

The lens element(s) of the front lens group may have larger sag andsteeper slope to collectively provide the UWFOV. In this regard, thefront lens group may be designed to provide a desired FOV for theimaging device. In an aspect, the front lens group may be referred to asa front fisheye group. The lens element(s) of the rear lens group maycollectively provide an FOV that is narrower than the FOV provided bythe front lens group. Thus, using various embodiments, lower costsassociated with WLO manufacturing may be achieved together withultra-wide FOV imaging by designing the lens element(s) of the reargroup lens to meet the rules associated with WLO manufacturing, whiledesigning the lens element(s) of the front group lens with the largersag and steeper slopes appropriate to allow image capture of anultra-wide FOV scene.

In some embodiments, forming the front lens group using one or morespherical lens elements allows for mitigation of calibration and gaincorrection process challenges that may be associated with an UWFOV. Byusing a spherical lens element(s), a calibration and gain correctionprocess may be performed using just the rear lens group (e.g., withoutthe front lens group). The front lens group may then be installed infront of the rear lens group after such a calibration and gaincorrection process. As further described herein, when the front lensgroup is formed of one or more spherical lens elements, a relativeillumination (RI) curve associated with just the rear lens group issubstantially the same as an RI curve associated with the front lensgroup together with the rear lens group. The property that the sphericalshape of the lens element(s) of the front lens group does not alter(e.g., has a minimal or no effect on) the resultant RI curve allows thecalibration and gain correction process to be performed with just therear lens group. A gain map may be determined based at least in part onthe RI curve determined using just the rear lens group. In this regard,the front lens group may be positioned in front of the rear lens groupafter calibration of the rear lens group without altering the gain mapdetermined from the calibration using just the rear lens group.

Using just the rear lens group allows for a calibration setup that isgenerally easier to implement than one that involves the front and rearlens groups. A calibration setup for a wide FOV lens element such as thefront lens element(s) involves capturing images of a correspondinglylarge blackbody (e.g., large flat uniform blackbody of a knowntemperature) that subtends the entire FOV produced by the wide FOV lenselement whereas the calibration setup associated with using just therear lens group involves capturing images of a smaller blackbody (e.g.,more readily available and/or easier to implement than a largerblackbody) that subtends the smaller FOV produced by the rear lens group(e.g., compared to the FOV produced by the rear lens group together withthe front lens group). As such, using various embodiments, arrangementsof lens elements as set forth in accordance with various embodiments mayallow beneficial cost and process (e.g., manufacturing process, gaincalibration process) characteristics in relation to imaging device(e.g., UWFOV LWIR cameras) manufacturing and operation.

Although various embodiments are described primarily with respect toinfrared imaging, methods and systems disclosed herein may be utilizedin conjunction with devices and systems such as imaging systems havingvisible-light and infrared imaging capability, mid-wave infrared (MWIR)imaging systems, short-wave infrared (SWIR) imaging systems, lightdetection and ranging (LIDAR) imaging systems, radar detection andranging (RADAR) imaging systems, millimeter wavelength (MMW) imagingsystems, ultrasonic imaging systems, X-ray imaging systems, microscopesystems, mobile digital cameras, video surveillance systems, videoprocessing systems, or other systems or devices that may need to obtainimage data in one or multiple portions of the EM spectrum.

Referring now to the drawings, FIG. 1 illustrates a block diagram of animaging device 100 in accordance with one or more embodiments of thepresent disclosure. In an embodiment, the imaging device 100 may be aninfrared imaging device. The imaging device 100 may be used to captureand process image frames. The imaging device 100 includes opticalcomponents 105, an image capture component 110, an image captureinterface component 115, and an optional shutter component 120.

The optical components 105 may receive electromagnetic radiation throughan aperture 125 of the imaging device 100 and pass the electromagneticradiation to the image capture component 110. For example, the opticalcomponents 105 may direct and/or focus electromagnetic radiation on theimage capture component 110. The optical components 105 may include oneor more windows, lenses, mirrors, beamsplitters, beam couplers, and/orother components. In an embodiment, the optical components 105 mayinclude one or more chalcogenide lenses, such as lenses made ofAs₄₀Se₆₀, that allow for imaging in a wide infrared spectrum. Othermaterials, such as silicon, germanium, and GeAsSe, may be utilized. Theoptical components 105 may include components each formed of materialand appropriately arranged according to desired transmissioncharacteristics, such as desired transmission wavelengths and/or raytransfer matrix characteristics.

The image capture component 110 includes, in one embodiment, one or moresensors (e.g., visible-light sensor, infrared sensor, or other type ofdetector) for capturing image signals representative of an image of ascene 130. The image capture component 110 may capture (e.g., detect,sense) infrared radiation with wavelengths in the range from around 700nm to around 1 mm, or portion thereof. For example, in some aspects, theimage capture component 110 may include one or more sensors sensitive to(e.g., better detect) thermal infrared wavelengths, including LWIRradiation (e.g., electromagnetic radiation with wavelength of 7-14 μm).The sensor(s) of the image capture component 110 may represent (e.g.,convert) or facilitate representation of a captured thermal image signalof the scene 130 as digital data (e.g., via an analog-to-digitalconverter).

The image capture interface component 115 may receive image datacaptured at the image capture component 110 and may communicate thecaptured image data to other components or devices, such as via wiredand/or wireless communication. In various embodiments, the imagingdevice 100 may capture image frames, for example, of the scene 130.

In some embodiments, the optical components 105, image capture component110, and image capture interface component 115 may be housed in aprotective enclosure. In one case, the protective enclosure may includea lens barrel (e.g., also referred to as a lens housing) that houses theoptical components 105 and a housing that houses the image capturecomponent 110 and/or the image capture interface component 115. In thiscase, the lens barrel may be coupled to the housing. In an aspect, theprotective enclosure may be represented by the solid-line box in FIG. 1having the aperture 125. For example, the aperture 125 may be an openingdefined in the protective enclosure that allows electromagneticradiation to reach the optical components 105. In some cases, theaperture 125 may be an aperture stop of the imaging device 100.

Each optical element (e.g., lens element) may include at least onemating feature (e.g., also referred to as a mounting feature). The lensbarrel may have a corresponding mating feature(s) that couples to amating feature(s) of the optical element(s) to receive and secure theoptical element(s). In this regard, each mating feature of an opticalelement may couple to a corresponding mating feature of the lens barrelto couple the optical element to the lens barrel. In one example, amating feature of an optical element may include a first surface and asecond surface at an angle (e.g., 90° angle, obtuse angle, or acuteangle) relative to the first surface, and a mating feature of a lensbarrel may have corresponding surfaces to couple to the first and secondsurfaces. In another example, a mating feature of an optical element mayinclude a pin portion, and a mating feature of a lens barrel may includea slot portion to receive the pin portion, and/or vice versa. Moregenerally, a mating feature(s) of an optical element and a correspondingmating feature(s) of a lens barrel may be any structure (e.g.,indentation, hole, pin, or other structure) that facilitates coupling ofthe optical element to the lens barrel.

In some cases, a mating feature of a lens element may be appropriate tofacilitate rotation and/or other movement of the lens element. In somecases, a mating feature may be utilized to facilitate alignment of alens element, such as via pattern recognition during molding, machining,and/or assembling. For example, one or more mating features on a surfaceof a lens element can be located (e.g., using pattern recognition toscan the surface) to facilitate machining of a different surface of thelens element according to a desired design. As another example, a matingfeature(s) of a surface(s) of a first lens element and/or a matingfeature(s) of a surface(s) of a second lens element may be utilized tofacilitate alignment of the first lens element relative to the secondlens element.

The shutter component 120 may be operated to selectively inserted intoan optical path between the scene 130 and the optical components 105 toexpose or block the aperture 125. In some cases, the shutter component120 may be moved (e.g., slid, rotated, etc.) manually (e.g., by a userof the imaging device 100) and/or via an actuator (e.g., controllable bya logic device in response to user input or autonomously, such as anautonomous decision by the logic device to perform a calibration of theimaging device 100). When the shutter component 120 is outside of theoptical path to expose the aperture 125, the electromagnetic radiationfrom the scene 130 may be received by the image capture component 110(e.g., via one or more optical components and/or one or more filters).As such, the image capture component 110 captures images of the scene130. The shutter component 120 may be referred to as being in an openposition or simply as being open. When the shutter component 120 isinserted into the optical path to block the aperture 125, theelectromagnetic radiation from the scene 130 is blocked from the imagecapture component 110. As such, the image capture component 110 capturesimages of the shutter component 120. The shutter component 120 may bereferred to as being in a closed position or simply as being closed.

In some aspects, the shutter component 120 may block the aperture 125during a calibration process, in which the shutter component 120 may beused as a uniform blackbody (e.g., a substantially uniform blackbody).For example, the shutter component 120 may be used as a singletemperature source or substantially single temperature source. In somecases, the shutter component 120 may be temperature controlled toprovide a temperature controlled uniform blackbody (e.g., to present auniform field of radiation to the image capture component 110). Forexample, in some cases, a surface of the shutter component 120 imaged bythe image capture component 110 may be implemented by a uniformblackbody coating. In some cases, such as for an imaging device withouta shutter component or with a broken shutter component or as analternative to the shutter component 120, a case or holster of theimaging device 100, a lens cap, a cover, a wall of a room, or othersuitable object/surface may be used to provide a uniform blackbody(e.g., substantially uniform blackbody) and/or a single temperaturesource (e.g., substantially single temperature source).

Although in FIG. 1 the shutter component 120 is positioned in front of(e.g., closer to the scene 130 than) all the optical components 105, theshutter component 120 may be positioned between optical components. Forexample, the optical components 105 may include a first group of one ormore lens elements and a second group of one or more lens elements, withthe shutter component 120 selectively inserted between a last lens ofthe first group of lens element(s) and a first lens of the second groupof lens element(s). Further, alternatively or in addition, although theshutter component 120 is positioned on or in proximity to an externalsurface of a housing of the imaging device 100, the shutter component120 may be positioned within the housing of the imaging device 100. Insome aspects, the imaging device 100 may include no shutter componentsor more than one shutter component.

The imaging device 100 may represent any type of camera system which,for example, detects electromagnetic radiation (e.g., thermal radiation)and provides representative data (e.g., one or more still image framesor video image frames). For example, the imaging device 100 may beconfigured to detect visible light and/or infrared radiation and provideassociated image data. In some cases, the imaging device 100 may includeother components, such as a heater, a temperature sensor (e.g., formeasuring an absolute temperature of a component of the imaging device100), a filter, a polarizer, and/or other component. For example, anintegrated heater may be coupled to the barrel of the imaging device100.

FIG. 2 illustrates a perspective view of an imaging device 200 inaccordance with one or more embodiments of the present disclosure. Asone example, the imaging device 200 may be an LWIR thermal camera (e.g.,for capturing electromagnetic radiation with wavelengths of 7-14 μm). Inother cases, the imaging device 200 may be utilized to captureelectromagnetic radiation within other wavelength ranges.

The imaging device 200 may include a lens barrel 205 configured toaccommodate at least a lens element 210. The lens barrel 205 may includea structure to hold/secure (e.g., fixedly secure, movably secure) thelens element 210. The imaging device 200 also may include an imagecapture portion 215 including an image capture component configured tocapture images viewed through the lens barrel 205. The image captureportion 215 may include arrays of microbolometers configured to detectEM radiation. As one example, the arrays of microbolometers may beconfigured to detect long-wave infrared light of wavelengths between 7.5μm and 13.5 μm. In an embodiment, the lens barrel 205 may be the lensbarrel of the imaging device 100 of FIG. 1 . In an embodiment, theimaging device 200 may be the imaging device 100 of FIG. 1 . In thisembodiment, the optical components 105 of FIG. 1 may include at leastthe lens element 210, and the image capture component 110 of FIG. 1 mayinclude the image capture portion 215.

In some cases, the lens barrel 205 may be configured to accommodate awindow in front of (e.g., closer to a scene than) the lens element 210.The window may selectively pass electromagnetic radiation of the scene.In some cases, the window may be a protective window placed in front ofthe lens element 210 to protect the lens element 210 and/or othercomponents of the imaging device 200 from environmental damage,mechanical damage, and/or other damage. Physical properties (e.g.,material composition, thickness and/or other dimensions, etc.) of thewindow may be determined based on a waveband(s) desired to betransmitted through the window. The lens barrel 205 may includestructure to hold/secure (e.g., fixedly secures, movably secures) thewindow and/or the lens element 210.

FIG. 3 illustrates a cross-sectional view of an optical system 300 inaccordance with one or more embodiments of the present disclosure. Theoptical system 300 is oriented along three orthogonal directions,denoted as X, Y, and Z. The X-direction and the Y-direction may bereferred to as the horizontal direction and the vertical direction,respectively. In particular, FIG. 3 illustrates a cross-sectional viewof the optical system 300 in the YZ-plane. The optical system 300includes a front lens group 305, a rear lens group 310, a window 315, adetector array 320, and a shutter component 325. In an embodiment, theoptical components 105 of FIG. 1 may include the front lens group 305,rear lens group 310, and window 315, and the image capture component 110of FIG. 1 may include the detector array 320.

The front lens group 305 includes a lens element 335. The front lensgroup 305 may provide a wide FOV, such as an UWFOV. In some aspects, thelens element 335 may be a spherical lens element. The spherical lenselement may be formed by grinding/polishing processes. In some cases,both surfaces of the lens element 335 may be spherical. The rear lensgroup 310 includes lens elements 340 and 345. In some aspects, the lenselements 340 and 345 may be aspherical lens elements. The lens elements340 and 345 may be formed by WLO processes. In a case that the lenselements 340 and 345 are different, the lens elements 340 and 345 may beformed as part of one wafer-level procedure (e.g., a wafer-levelprocedure that can be used to obtain differently shaped and/or sizedlens elements) or two separate wafer-level procedures. The lens elements340 and 345 form a doublet. Each of the lens elements 335, 340, and 345(e.g., and other optical components not labeled or shown in FIG. 3 ) mayhave specific optical characteristics, such as a specific effectivefocal length (EFL) and a transmitted wavefront. In general, eachadditional lens element provided may allow more degrees of freedom withregard to characteristics (e.g., shape such as curvature, size) definedfor each of the lens elements to achieve a desired performance. Examplesof materials of the lens elements 335, 340, and/or 345 may includeAs₄₀Se₆₀, Ge₂₂As₂₀Se₅₈, Ge₃₃As₁₂Se₅, germanium, zinc selenide, silicon,polyethylene, and TPX. In some cases, one or more coatings may bedisposed on the lens elements 335, 340, and/or 345. By way ofnon-limiting examples, a coating may be an anti-reflective (AR) coating,a polarization coating, impact-resistant coating, and/or other coating.

The lens elements 335, 340, and 345 may coordinate to direct and focusinfrared light onto the detector array 320. The lens element 335receives the electromagnetic radiation and directs the receivedelectromagnetic radiation to the lens element 340 of the rear lens group310. The lens element 340 receives the electromagnetic radiation fromthe lens element 335 and directs the electromagnetic radiation receivedfrom the lens element 335 to the lens element 345. The lens element 345receives the electromagnetic radiation from the lens element 340 anddirects the electromagnetic radiation received from the lens element 340to the detector array 320. As such, the front lens group 305 and therear lens group 310 collectively project the scene onto the detectorarray 320. In this regard, FIG. 3 illustrates at least a portion of ascene ray traced through the front lens group 305 and the rear lensgroup 310 to the detector array 320. As shown in FIG. 3 , the lenselement 335 may be a refractive lens element. The lens elements 340 and345 may be plano-convex lens elements. The lens element 335 has asurface A and a surface B opposite the surface A. The surface A of thelens element 335 faces the scene. The lens element 340 has a surface Dand a surface E opposite the surface D. The surface D of the lenselement 340 faces the surface B of the lens element 335. The lenselement 345 has a surface I and a surface J opposite the surface I. Thesurface I of the lens element 345 faces the surface E of the lenselement 340. The surface J of the lens element 340 faces the window 315.

As a non-limiting example, a distance between the surface B of the lenselement 335 and the surface D of the lens element 340 may be betweenaround 4 mm and around 5 mm. As a non-limiting example, a thickness ofeach of the lens elements 340 and 345 may be between around 0.5 mm andaround 1.5 mm. The thickness of the lens elements 340 and 345 isgenerally selected for lower mass (e.g., associated with lower costs)while providing sufficient mechanical stability. As a non-limitingexample, a size L (e.g., extending from around a bottom surface to a topsurface of the lens element 335) may be from around 7 mm to around 500mm. As a non-limiting example, a size H (e.g., extending from around thesurface A of the lens element 335 to the surface J of the lens element345) may be from around 5 mm to 300 mm. The dimensions of H and Lgenerally depend on an image diagonal of the detector array 320. For agiven pixel size, a larger pixel count is generally associated with alarger lens. As one example, L may be referred to as a length of animaging device (e.g., a camera) and H may be referred to as a height ofthe imaging device, or vice versa L may be referred to as the height andH may be referred to as the length. As a non-limiting example, athickness of the window 315 may be from around 0.4 mm to around 1 mm. Asa non-limiting example, a gap between the window 315 and the detectorarray 310 may be around 0.1 mm.

The window 315 is disposed in front of the detector array 320 toselectively pass electromagnetic radiation to the detector array 320.Physical properties (e.g., material composition, thickness and/or otherdimensions, etc.) of the window 315 may be determined based on awaveband(s) desired to be transmitted through the window 315. The window315 may be provided as a lid for the detector array 320. The window 315may be provided to protect the detector array 320 and form a vacuumbetween sensors (e.g., microbolometers) of the detector array 320 andthe window 315. In some cases, the window 315 may be used to providefiltering, polarization, and/or other optical effects in addition toprotection. In some cases, one or more coatings (e.g., polarizationcoating, AR coating, impact-resistant coating) may be disposed on thewindow 315 to provide the filtering, polarization, protection, and/orother effects.

The detector array 320 receives the electromagnetic radiation andgenerates an image based on the electromagnetic radiation. In an aspect,the image may be processed using processing circuitry downstream of thedetector array 320. As non-limiting examples, the detector array 320 mayhave a size of 160×120 sensors (e.g., 160×120 array of microbolometers),320×256 sensors, and 1280×1024 sensors.

Although, in the optical system 300, the front lens group 305 has asingle lens and the rear lens group 310 has two lens elements, in someembodiments, the front lens group 305 has more than one lens elementand/or the rear lens group 310 has more or fewer than two lens elements.As one example, providing more lens elements (e.g., one or moreadditional spherical lens elements) in the front lens group 305 mayfacilitate broadening of the FOV associated with the front lens group305. In this regard, each additional lens element may facilitatebroadening of the FOV associated with the front lens group 305. As oneexample, alternative or in addition to providing more lens elements inthe front lens group 305, providing more lens elements (e.g., one ormore additional aspherical lens elements) in the rear lens group 310 mayallow projection of the electromagnetic radiation onto a larger detectorarray (e.g., having more rows and/or more columns of sensors).

The shutter component 325 may be operated to selectively inserted intoan optical path between the scene and the rear lens group 310 to exposeor block the scene from the detector array 320. In some cases, theshutter component 325 may be moved (e.g., slid, rotated, etc.) manually(e.g., by a user) and/or via an actuator (e.g., controllable by a logicdevice in response to user input or autonomously, such as an autonomousdecision by the logic device to perform a calibration of an imagingdevice). In some aspects, the shutter component 325 may block thedetector array 320 from the scene during a calibration process, in whichthe shutter component 325 may be used as a uniform blackbody (e.g., asubstantially uniform blackbody), as further described herein.

An aperture stop 350 is positioned/defined in front of the rear lensgroup 310. The aperture stop 350 defines an amount of light that istransmitted to the detector array 320. The aperture stop 350 may havespatial dimensions comparable to spatial dimensions of the rear lensgroup 310. The aperture stop 350 may be defined by physical propertiesof the lens element 340, such as a size, shape, and material of thefront surface of the lens element 340, and physical properties of astructure that holds the lens element 340. For instance, the structuremay be a part of a lens barrel (e.g., the lens barrel 200). In one case,the structure may be a metal structure at least partially in front ofthe lens element 340. As one example, the structure may be a metalstructure that has a shape that conforms to the front surface of thelens element 340.

In an embodiment, to facilitate alignment of a horizontal field of viewwith the horizontal direction of the detector array 320 and a verticalfield of view with the vertical direction of the detector array 320, thelens elements 335, 340, and/or 345 can be moved relative to the detectorarray 320. In some aspects, the lens elements 335, 340, and/or 345 maybe moved via sliding motion (e.g., translational motion) to facilitatefocusing, such as by using one or more actuators coupled to the lenselements 335, 340, and/or 345. In one case, the sliding motion may bealong the Z-axis (e.g., the direction perpendicular to a focal plane)while preserving a fixed angular orientation. In these aspects, afocusing mechanism of the lens elements 335, 340, and/or 345 may includecomponents (e.g., actuators) for moving the lens elements 335, 340,and/or 345. In some aspects, one or more lenses may be focused byrotating the lens(es) inside a threaded housing. In some aspects, thehousing is not threaded. The housing may allow a linear slip-fit typearrangement rather than a threaded-in type arrangement, in which thelens elements 335, 340, and/or 345 may be pushed into the housing andmaintained in place using at least friction. Alternatively, some gap maybe provided between the barrel and housing to allow for active alignmentof the optics to the detector array 320 which is fixed in place by epoxyor other suitable adhesive.

In some embodiments, the lens elements 335, 340, and 345 are eachassociated with a lens prescription. In some aspects, each prescriptionmay be expressed according to the following:

$Z = {\frac{cS^{2}}{1 + \sqrt{1 - {\left( {K + 1} \right)c^{2}S^{2}}}} + {A_{1}S^{4}} + {A_{2}S^{6}} + {A_{3}S^{8}} + {A_{4}S^{10}} + \ldots + {A_{12}S^{26}}}$

where S=x²+y²; c=1/r; r is the radius of curvature; A₁, A₂, A₃, A₄, . .. , A₁₂ are aspheric deformation constants; and K is the conic constant.

Table 1 illustrates example values of various parameters of the opticalsystem 300. For example, as shown in Table 1 below, the surface E of thelens element 340 and the surface J of the lens element 345 are flatsurfaces and thus have zero coefficients.

Coefficient Surface A Surface B Surface E Surface F Surface I Surface Jc 0.0715839 0.1797383 0 −0.192847 0.2789283 0 k 0 0 0 0 0 0 A₁ 0 0 0−1.082E−03 −9.136E−03 0 A₂ 0 0 0 0 0 0 A₃ 0 0 0 0 0 0 A₄ 0 0 0 0 0 0 A₅0 0 0 0 0 0 A₆ 0 0 0 0 0 0 A₇ 0 0 0 0 0 0

FIG. 4 illustrates an FOV, denoted as a, associated with (e.g., providedby) the optical system 300 of FIG. 3 in accordance with one or moreembodiments of the present disclosure. The FOV α depicted in FIG. 4 isaround 160°. More generally, in some embodiments, the FOV α may bebetween around 110° to around 220°. In this regard, in some embodiments,the optical system 300 may be designed to provide a field of view α thatexceeds 180° to allow an imaging device including the optical system 300to capture scene data (e.g., image data in the form of electromagneticradiation) behind the imaging device. In some aspects, the field of viewα may be between around 120° to around 160°.

FIG. 5 illustrates a field of view, denoted as β, associated with therear lens group 310 of the optical system 300 of FIG. 3 . The FOV βdepicted in FIG. 5 is around 60°. In some embodiments, the FOV β may bebetween around 50° to around 70°.

In some embodiments, a gain calibration process may be performed on theoptical system 300. In some aspects, the gain calibration process mayinvolve using an imaging device to capture images of a flat uniformblackbody to create a gain map that is stored in a pipeline. To make asignal flat across an entire detector array, a signal drop due torelative illumination is compensated with gain. RI refers to an effectin which a lens element has illumination roll-off from the centertowards the corner field. When the lens element 335 (e.g., and any otherlens element of the front lens group 305) is a spherical lens element, acalibration process, such as a gain calibration process, may beperformed based on just the rear lens group 310 (e.g., rather than therear lens group 310 together with the front lens group 305). In suchembodiments, due to the spherical shape of the lens element 335, the RIcurve associated with the optical system 300 including the lens element335 and the rear lens group 310 is substantially the same as an RI curveassociated with only the rear lens group 310. As an example, FIG. 6illustrates a graph 600 with an RI curve 605 associated with a lenssystem including the lens element 335 and the rear lens group 310 and anRI curve 610 associated with just the rear lens group 310. The RI curves605 and 610 are substantially identical (e.g., substantiallyoverlap/overlay each other).

A gain map may be determined based at least in part on the RI curvedetermined using just the rear lens group 310. In this regard, the frontlens group 305 may be positioned in front of the rear lens group 310after calibration of the rear lens group 310 without altering the gainmap determined from the calibration. Thus, since the lens element 335does not alter the RI curve, the gain calibration may be performed usingjust the rear lens group 310 rather than the rear lens group 310together with the lens element 335. Using just the rear lens group 310allows for a calibration setup that is generally easier to implement,since a calibration setup for a wide FOV lens element such as the lenselement 335 involves capturing images of a correspondingly largeblackbody (e.g., large flat uniform blackbody) that subtends the entireFOV produced by the wide FOV lens element. The calibration setupassociated with using just the rear lens group 310 (e.g., as shown inFIG. 4 ) involves capturing images of a smaller blackbody that subtendsthe smaller FOV produced by the rear lens group 310 (e.g., compared toFOV produced by the rear lens group 310 together with the lens element335). In some cases, use of a smaller blackbody allows for costeffective batch-level calibration.

The calibration setup may include a reference object (e.g., alsoreferred to as a reference source) positioned in the field of view ofthe detector array 320. The reference object may be at a knowntemperature (e.g., accurately measured and/or controllable temperature)and provide a uniform blackbody. In this regard, the reference objectmay be used as a single temperature source or substantially singletemperature source. In some cases, the reference object may be theshutter component 325 (e.g., an integrated shutter) that is selectivelyclosed to block the detector array 320. A logic device may control anactuator to close the shutter component 325 or the user may manuallyclose the shutter component 325 (e.g., by manually controlling theactuator or manually closing the shutter component 325). In some cases,the reference source may be an external reference object provided in thescene. Such an external object may be referred to as, or referred to asproviding, an external shutter.

Although the foregoing describes performing the gain calibration processusing just the rear lens group 310 and then installing the front lensgroup 305, in other embodiments, appropriate equipment, environment,and/or image device design may be readily available such that a gaincalibration process may be performed on the rear lens group 310 togetherwith the front lens group 305.

In some embodiments, use of a spherical prescription for a front lenselement(s) of the front lens group 305 may allow for low sensitivity oflens performance to figure errors in the prescription(s) of the frontlens element(s) and its/their respective position relative to rear lenselements of the rear lens group 310. As an example, FIGS. 7A through 7Feach illustrates a graph showing a low sensitivity of a performancemetric (e.g., modulation transfer function, FOV, or RI) to figure errorsand position of the lens element 335 (e.g., relative to the rear lensgroup 310). For explanatory purposes, the lens element 335 has theprescription provided in Table 1. FIG. 7A illustrates a graph 705showing a low sensitivity of an on-axis modulation transfer function(MTF) in relation to a radius (e.g., in mm) associated with the surfaceA, denoted as A radius, and a radius (e.g., in mm) associated with thesurface B, denoted as B radius. FIG. 7B illustrates a graph 710 showinga low sensitivity of the on-axis MTF in relation to a thickness of thelens element 335, denoted as AB thickness (e.g., a distance between thesurface A and surface B), and a distance between the surface B of thelens element 335 and the surface E of the lens element 340, denoted asB-E airgap. FIG. 7C illustrates a graph 715 showing a low sensitivity ofthe RI in relation to the AB thickness and the B-E airgap. FIG. 7Dillustrates a graph 720 showing a low sensitivity of the FOV in relationto the A radius and the B radius. FIG. 7E illustrates a graph 725showing a low sensitivity of the FOV in relation to the AB thickness andthe B-E airgap. FIG. 7F illustrates a graph 730 showing a lowsensitivity of the RI in relation to the A radius and the B radius. Insome embodiments, such low sensitivity may be leveraged to allowfocusing of a lens system including the front lens group 305 and therear lens group 310 using automated focusing equipment (e.g., costeffective automated focusing equipment) as part of manufacturing of animaging device that includes the lens system.

FIG. 8 illustrates a cross-sectional view of an imaging device 800 inaccordance with one or more embodiments of the present disclosure. Notall of the depicted components may be required, however, and one or moreembodiments may include additional components not shown in the figure.Variations in the arrangement and type of the components may be madewithout departing from the spirit or scope of the claims as set forthherein. Additional components, different components, and/or fewercomponents may be provided.

The imaging device 800 includes a lens barrel 805, the window 315, andthe detector array 320. The window 315 and the detector array 320 aredisposed in a housing 810 (e.g., camera housing) of the imaging device800. The lens barrel 805 includes body portions 815 and 820. The lensbarrel 805 (e.g., the body portions 815 and/or 820) includes astructure(s) to hold/secure (e.g., fixedly secure, movably secure)optical elements, such as lens elements. The body portion 815 may bereferred to as a front body portion or a top body portion, and the bodyportion 820 may be referred to as a rear body portion or a bottom bodyportion. The body portion 815 and the body portion 820 may be formed asseparate pieces that are then coupled together (e.g., using adhesives,engagement features, etc.). In FIG. 8 , the body portion 815 includesthe lens element 335 of the front lens group 305, and the body portion820 includes the lens elements 340 and 345 of the rear lens group 310.The lens barrel 805 may allow optical components disposed therein tomaintain axial position and/or air gap between them. In some cases, aportion (e.g., a portion of the body portion 820) of the lens barrel 805may be threaded to mate with a threaded portion of the housing 810. Suchthreading may facilitate focusing of the optical elements relative to afocal plane array.

FIG. 9 illustrates a flow diagram of an example process 900 formanufacturing the imaging device 800 of FIG. 8 in accordance with one ormore embodiments of the disclosure. For explanatory purposes, theexample process 900 is described herein with reference to components ofFIGS. 8, 10A, 10B, 10C, and 10D. FIGS. 10A, 10B, 10C, and 10D illustrateperspective views associated with manufacturing the imaging device 800.However, the example process 900 is not limited to the components ofFIGS. 8, 10A, 10B, 10C, and 10D.

At block 905, the detector array 320 is provided. At block 910, opticalcomponents are formed. The optical components may include one or morewindows (e.g., the window 315) and/or one or more lens elements (e.g.,the lens elements 335, 340, and 345). In some cases, the lens element335 may be a spherical lens element (e.g., spherical surface on bothsides) formed using grinding/polishing processes. In some cases, thelens elements 340 and 345 may be aspherical lens elements formed usingWLO processes. For LWIR imaging applications, the window 315 and thelens element 335, 340, and 345 may be formed from material that istransmissive in the 7-14 μm wavebands.

At block 915, the detector array 320 is disposed within the housing 810(e.g., camera housing) of the imaging device 800. The window 315 may beprovided as a lid for the detector array 320. The window 315 may beprovided to protect the detector array 320 and form a vacuum betweensensors (e.g., microbolometers) of the detector array 320 and the window315. In designing the optical system 300, a certain distance between thelens element 335 and the detector array 320 is allocated to support acertain thickness for the window 315. At block 920, with reference toFIG. 10A, the rear lens group 310 is at least partially disposed withinthe lens barrel 805 (e.g., the body portion 820 of the lens barrel 805).In some aspects, the lens elements 340 and 345 may each have matingfeatures to couple to corresponding mating features of the lens barrel805. At block 925, the body portion 820 of the lens barrel 805 iscoupled to the housing 810.

At block 930, with reference to FIG. 10B, a collet 1005 with a frontlens element 1010 positioned therein is coupled/engaged to the bodyportion 820 of the lens barrel 805 to allow an accurate focusing of athree-lens system formed of the lens elements 340 and 345 and the frontlens element 1010. As a result of a focusing process, the three-lenssystem is focused relative to the detector array 320. During focusing,the collet 1005 may be engaged with the body portion 820 of the lensbarrel 805 using torque locking features (not shown) so that thethree-lens system is focused relative to the detector array 320. Thecollet 1005 may provide a standard reference for facilitating focusingrear lens groups to the front lens element 1010. It is noted thatdisposing of the lenses 340 and 345 within the body portion 820 of thelens barrel 805 at block 920 need not be accurate. A position of thelens elements 340 and 345 may be determined/estimated based on anapproximate number of threaded turns. More precise positioning of thelens elements 340 and 345 (e.g., relative to the front lens element 1010and the detector array 320) may be performed at block 930.

At block 935, with reference to FIG. 10C, the collet 1005 with the frontlens element 1010 is removed (e.g., decoupled/disengaged from the bodyportion 820 of the lens barrel 805) after the focusing process. As aresult of the focusing, the lens elements 340 and 345 of the rear lensgroup 310 are appropriately positioned (e.g., at a focusing back workingdistance) relative to the detector array 320. At block 940, a gaincorrection/calibration of the rear lens group 310 is performed with therear lens group 310 positioned according to the focusing performed atblock 930 to obtain a gain map. To perform the calibration, a referenceobject (e.g., internal shutter, external shutter, or other object) maybe positioned on the FOV of the rear lens group 310 and image datacaptured by directing electromagnetic radiation to the detector array320 using the rear lens group 310. The gain map may be determined (e.g.,using a logic device of and/or coupled to the imaging device 800) basedon the image data. Due to use of the front lens element 910 forfacilitating focusing and calibration, the front lens element 910 may bereferred to as a reference lens element or a calibration lens element.

At block 945, the front lens group 305 is at least partially disposedwithin the body portion 815 of the lens barrel 805. At block 950, withreference to FIG. 10D, the body portion 815 of the lens barrel 805 withthe front lens group 305 disposed therein is coupled to the body portion820 of the lens barrel 805. The imaging device 800 is formed and may beused to capture images. Gain correction may be performed on these imagesusing the gain map determined at block 940 based on the rear lens group310 (e.g., without the front lens group 305 installed). In some cases,the front lens group 305 may be focused slightly after installationbefore the imaging device 800 is used. In some aspects, due to a lowsensitivity of the design to figure errors of a front lens element andits position, an impact of variations in geometrical errors in thepopulation is generally minuscule (e.g., assuming the front lenselements are manufactured within appropriate tolerances). In someaspects, due to such low sensitivity, the lens element 335 of the frontlens group 305 may be selected (e.g., randomly selected) from apopulation of lens elements manufactured according to a prescriptionassociated with a desired front group lens element. In this regard, therear lens group 310 may form a lens system with any lens elementsmanufactured according to a prescription associated with a desired frontgroup lens element with minimal or no further adjustment needed beforeuse of the lens system including the front group lens element and therear lens group 310. Each lens element of the population may be producedby a vendor(s) within a certain margin of error. It is noted that thecalibration at block 940 may be performed at the factory and/orin-the-field. In some cases, in-the-field calibration may be performedusing the lens element 335 and without the collet 1005.

FIG. 11 illustrates a flow diagram of an example process 1100 for usingthe imaging device 800 of FIG. 8 in accordance with one or moreembodiments of the present disclosure. For explanatory purposes, theexample process 1100 is primarily described herein with reference to theimaging device 800. However, the example process 1100 is not limited tothe imaging device 800 of FIG. 8 . At block 1105, a lens systemincluding the front lens group 305 and the rear lens group 310 receiveselectromagnetic radiation associated with a scene and directs theelectromagnetic radiation to the detector array 320. At block 1110, thedetector array 320 receives the electromagnetic radiation from the lenssystem. In this regard, each detector of the detector array 320 mayreceive a portion of the electromagnetic radiation from the lens system.At block 1115, the detector array 320 generates an image based on theelectromagnetic radiation and a gain map. In some aspects, the gain mapmay be determined (e.g., at block 940) based on a calibration of therear lens group 310 (e.g., without the front lens group 305 installed).In some aspects, the lens system may be appropriate to transmit thermalinfrared radiation and the image generated by the detector array 320 maybe a thermal infrared image. In some cases, the image generated by thedetector array 320 may be provided for processing, storage, and/ordisplay. For example, the image may be provided to a processor forprocessing to remove distortion in the image, and the processed imagemay then be provided for storage, display, and/or further processing.

Although, in the optical system 300 referenced in FIG. 3 and variousother figures, the front lens group 305 has a single lens and the rearlens group 310 has two lens elements, in some embodiments, the frontlens group 305 has more than one lens element and/or the rear lens group310 has more or fewer than two lens elements.

In an aspect, providing more lens elements (e.g., one or more additionalspherical lens elements) in the front lens group 305 may facilitatebroadening of the FOV associated with the front lens group 305. In thisregard, each additional lens element may facilitate broadening of theFOV associated with the front lens group 305. As an example, FIG. 12illustrates a cross-sectional view of an optical system 1200 inaccordance with one or more embodiments of the present disclosure. Thedescription of FIG. 3 generally applies to FIG. 12 , with examples ofdifferences and other description provided herein. The optical system1200 includes a front lens group 1205, a rear lens group 1210, a window1215, a detector array 1220, and a shutter component 1225. In anembodiment, the front lens group 1205, the rear group lens 1210, thewindow 1215, the detector array 1220, and the shutter component 1225 maybe, may provide the same or similar functionality as, and/or mayotherwise correspond to the front lens group 305, the rear group lens310, the window 315, the detector array 320, and the shutter component325, respectively.

The front lens group 1205 includes lens elements 1235 and 1240. Thefront lens group 1205 may provide a wide FOV, such as an UWFOV. In someaspects, the lens element 1235 and 1240 may spherical lens elements. Thespherical lens elements may be formed by grinding/polishing processes.In some cases, both surfaces of the lens elements 1235 and 1240 may bespherical. Relative to the front lens group 305 of FIG. 3 that includesa single front lens element, the additional lens element 1240 mayfacilitate broadening of the FOV. The rear lens group 1210 includes lenselements 1245 and 1250. In some aspects, the lens elements 1245 and 1250may be aspherical lens elements. The lens elements 1245 and 1250 may beformed by WLO processes. In an embodiment, the lens element 1235 mayhave the same or similar prescription/properties (e.g., materialproperties, applied coatings, etc.) as the lens element 335, the lenselement 1245 may have the same or similar prescription/properties as thelens element 340, and/or the lens element 1250 may have the same orsimilar prescription/properties as the lens element 345.

The lens elements 1235, 1240, 1245, and 1250 may coordinate to directand focus infrared light onto the detector array 1220. The lens element1235 receives the electromagnetic radiation and directs the receivedelectromagnetic radiation to the lens element 1240. The lens element1240 receives the electromagnetic radiation from the lens element 1235and directs the received electromagnetic radiation to the lens element1245. The lens element 1245 receives the electromagnetic radiation fromthe lens element 1240 and directs the electromagnetic radiation receivedfrom the lens element 1240 to the lens element 1250. The lens element1250 receives the electromagnetic radiation from the lens element 1245and directs the electromagnetic radiation received from the lens element1245 to the detector array 1220. As such, the front lens group 1205 andthe rear lens group 1210 collectively project the scene onto thedetector array 1220. In this regard, FIG. 12 illustrates at least aportion of a scene ray traced through the front lens group 1205 and therear lens group 1210 to the detector array 1220. An aperture stop 1255is positioned/defined in front of the rear lens group 1210. The aperturestop 1255 defines an amount of light that is transmitted to the detectorarray 1220. The aperture stop 1255 may have spatial dimensionscomparable to spatial dimensions of the rear lens group 1210.

In an aspect, alternative or in addition to providing more lens elementsin the front lens group 305, more lens elements may be provided in therear lens group 310. Providing more lens elements (e.g., one or moreadditional aspherical lens elements) in the rear lens group 310 mayallow projection of the electromagnetic radiation onto a larger detectorarray (e.g., having more rows and/or more columns of sensors). As anexample, FIG. 13 illustrates a cross-sectional view of an optical system1300 in accordance with one or more embodiments of the presentdisclosure. The description of FIGS. 3 and 12 generally applies to FIG.13 , with examples of differences and other description provided herein.The optical system 1300 includes a front lens group 1305, a rear lensgroup 1310, a window 1315, a detector array 1320, and a shuttercomponent 1325. In an embodiment, the front lens group 1305, the reargroup lens 1310, the window 1315, the detector array 1320, and theshutter component 1325 may be, may provide the same or similarfunctionality as, and/or may otherwise correspond to the front lensgroup 305, the rear group lens 310, the window 315, the detector array320, and the shutter component 325, respectively.

The front lens group 1305 includes a lens element 1335. The front lensgroup 1305 may provide a wide FOV, such as an UWFOV. In some aspects,the lens element 1335 may be a spherical lens element. The sphericallens element may be formed by grinding/polishing processes. In somecases, both surfaces of the lens element 1335 may be spherical. The rearlens group 1310 includes lens elements 1340, 1345, and 1350. In someaspects, the lens elements 1340, 1345, and 1350 may be aspherical lenselements. The lens elements 1340, 1345, and 1350 may be formed by WLOprocesses. Relative to the rear lens group 310 of FIG. 3 that includestwo rear lens elements, the additional lens element 1345 may facilitateprojection of the electromagnetic radiation onto a larger detectorarray. In an embodiment, the lens element 1335 may have the same orsimilar prescription/properties (e.g., material properties, appliedcoatings, etc.) as the lens element 335, the lens element 1340 may havethe same or similar prescription/properties as the lens element 340,and/or the lens element 1350 may have the same or similarprescription/properties as the lens element 345.

The lens elements 1335, 1340, 1345, and 1350 may coordinate to directand focus infrared light onto the detector array 1320. The lens element1335 receives the electromagnetic radiation and directs the receivedelectromagnetic radiation to the lens element 1340. The lens element1340 receives the electromagnetic radiation from the lens element 1335and directs the received electromagnetic radiation to the lens element1345. The lens element 1345 receives the electromagnetic radiation fromthe lens element 1340 and directs the electromagnetic radiation receivedfrom the lens element 1340 to the lens element 1350. The lens element1350 receives the electromagnetic radiation from the lens element 1345and directs the electromagnetic radiation received from the lens element1345 to the detector array 1320. As such, the front lens group 1305 andthe rear lens group 1310 collectively project the scene onto thedetector array 1320. In this regard, FIG. 13 illustrates at least aportion of a scene ray traced through the front lens group 1305 and therear lens group 1310 to the detector array 1320. An aperture stop 1355is positioned/defined in front of the rear lens group 1310. The aperturestop 1355 defines an amount of light that is transmitted to the detectorarray 1320. The aperture stop 1355 may have spatial dimensionscomparable to spatial dimensions of the rear lens group 1310.

FIG. 14 illustrates a block diagram of an example imaging system 1400 inaccordance with one or more embodiments of the present disclosure. Notall of the depicted components may be required, however, and one or moreembodiments may include additional components not shown in the figure.Variations in the arrangement and type of the components may be madewithout departing from the spirit or scope of the claims as set forthherein. Additional components, different components, and/or fewercomponents may be provided.

The imaging system 1400 may be utilized for capturing and processingimages in accordance with an embodiment of the disclosure. The imagingsystem 1400 may represent any type of imaging system that detects one ormore ranges (e.g., wavebands) of EM radiation and providesrepresentative data (e.g., one or more still image frames or video imageframes). The imaging system 1400 may include an imaging device 1405. Byway of non-limiting examples, the imaging device 1405 may be, mayinclude, or may be a part of an infrared camera, a visible-light camera,a tablet computer, a laptop, a personal digital assistant (PDA), amobile device, a desktop computer, or other electronic device. Theimaging device 1405 may include a housing (e.g., a camera body) that atleast partially encloses components of the imaging device 1405, such asto facilitate compactness and protection of the imaging device 1405. Forexample, the solid box labeled 1405 in FIG. 14 may represent a housingof the imaging device 1405. The housing may contain more, fewer, and/ordifferent components of the imaging device 1405 than those depictedwithin the solid box in FIG. 14 . In an embodiment, the imaging system1400 may include a portable device and may be incorporated, for example,into a vehicle or a non-mobile installation requiring images to bestored and/or displayed. The vehicle may be a land-based vehicle (e.g.,automobile, truck), a naval-based vehicle, an aerial vehicle (e.g.,unmanned aerial vehicle (UAV)), a space vehicle, or generally any typeof vehicle that may incorporate (e.g., installed within, mountedthereon, etc.) the imaging system 1400. In another example, the imagingsystem 1400 may be coupled to various types of fixed locations (e.g., ahome security mount, a campsite or outdoors mount, or other location)via one or more types of mounts.

The imaging device 1405 includes, according to one implementation, alogic device 1410, a memory component 1415, an image capture component1420 (e.g., an imager, an image sensor device), an image interface 1425,a control component 1430, a display component 1435, a sensing component1440, and/or a network interface 1445. In an embodiment, the imagingdevice 1405 may be, may include, or may be a part of, the imaging device100 of FIG. 1 and/or the imaging device 800 of FIG. 8 . The logic device1410, according to various embodiments, includes one or more of aprocessor, a microprocessor, a central processing unit (CPU), a graphicsprocessing unit (GPU), a single-core processor, a multi-core processor,a microcontroller, a programmable logic device (PLD) (e.g., fieldprogrammable gate array (FPGA)), an application specific integratedcircuit (ASIC), a digital signal processing (DSP) device, or other logicdevice, one or more memories for storing executable instructions (e.g.,software, firmware, or other instructions), and/or or any otherappropriate combination of processing device and/or memory to executeinstructions to perform any of the various operations described herein.The logic device 1410 may be configured, by hardwiring, executingsoftware instructions, or a combination of both, to perform variousoperations discussed herein for embodiments of the disclosure. The logicdevice 1410 may be configured to interface and communicate with thevarious other components (e.g., 1415, 1420, 1425, 1430, 1435, 1440,1445, etc.) of the imaging system 1400 to perform such operations. Inone aspect, the logic device 1410 may be configured to perform varioussystem control operations (e.g., to control communications andoperations of various components of the imaging system 1400) and otherimage processing operations (e.g., debayering, sharpening, colorcorrection, offset correction, bad pixel replacement, data conversion,data transformation, data compression, video analytics, etc.).

The memory component 1415 includes, in one embodiment, one or morememory devices configured to store data and information, includinginfrared image data and information. The memory component 1415 mayinclude one or more various types of memory devices including volatileand non-volatile memory devices, such as random access memory (RAM),dynamic RAM (DRAM), static RAM (SRAM), non-volatile random-access memory(NVRAM), read-only memory (ROM), programmable read-only memory (PROM),erasable programmable read-only memory (EPROM), electrically-erasableprogrammable read-only memory (EEPROM), flash memory, hard disk drive,and/or other types of memory. As discussed above, the logic device 1410may be configured to execute software instructions stored in the memorycomponent 1415 so as to perform method and process steps and/oroperations. The logic device 1410 and/or the image interface 1425 may beconfigured to store in the memory component 1415 images or digital imagedata captured by the image capture component 1420.

In some embodiments, a separate machine-readable medium 1450 (e.g., amemory, such as a hard drive, a compact disk, a digital video disk, or aflash memory) may store the software instructions and/or configurationdata which can be executed or accessed by a computer (e.g., a logicdevice or processor-based system) to perform various methods andoperations, such as methods and operations associated with processingimage data. In one aspect, the machine-readable medium 1450 may beportable and/or located separate from the imaging device 1405, with thestored software instructions and/or data provided to the imaging device1405 by coupling the machine-readable medium 1450 to the imaging device1405 and/or by the imaging device 1405 downloading (e.g., via a wiredlink and/or a wireless link) from the machine-readable medium 1450. Itshould be appreciated that various modules may be integrated in softwareand/or hardware as part of the logic device 1410, with code (e.g.,software or configuration data) for the modules stored, for example, inthe memory component 1415.

The imaging device 1405 may be a video and/or still camera to captureand process images and/or videos of a scene 1475. In this regard, theimage capture component 1420 of the imaging device 1405 may beconfigured to capture images (e.g., still and/or video images) of thescene 1475 in a particular spectrum or modality. The image capturecomponent 1420 includes an image detector circuit 1465 (e.g., avisible-light detector circuit, a thermal infrared detector circuit) anda readout circuit 1470 (e.g., an ROIC). For example, the image capturecomponent 1420 may include an IR imaging sensor (e.g., IR imaging sensorarray) configured to detect IR radiation in the near, middle, and/or farIR spectrum and provide IR images (e.g., IR image data or signal)representative of the IR radiation from the scene 1475. For example, theimage detector circuit 1465 may capture (e.g., detect, sense) IRradiation with wavelengths in the range from around 700 nm to around 2mm, or portion thereof. For example, in some aspects, the image detectorcircuit 1465 may be sensitive to (e.g., better detect) SWIR radiation,MWIR radiation (e.g., EM radiation with wavelength of 2 μm to 5 μm),and/or LWIR radiation (e.g., EM radiation with wavelength of 7 μm to 14μm), or any desired IR wavelengths (e.g., generally in the 0.7 μm to 14μm range). In other aspects, the image detector circuit 1465 may captureradiation from one or more other wavebands of the EM spectrum, such asvisible light, ultraviolet light, and so forth.

The image detector circuit 1465 may capture image data (e.g., infraredimage data) associated with the scene 1475. To capture a detector outputimage, the image detector circuit 1465 may detect image data of thescene 1475 (e.g., in the form of EM radiation) received through anaperture 1480 of the imaging device 1405 and generate pixel values ofthe image based on the scene 1475. An image may be referred to as aframe or an image frame. In some cases, the image detector circuit 1465may include an array of detectors (e.g., also referred to as an array ofpixels) that can detect radiation of a certain waveband, convert thedetected radiation into electrical signals (e.g., voltages, currents,etc.), and generate the pixel values based on the electrical signals.Each detector in the array may capture a respective portion of the imagedata and generate a pixel value based on the respective portion capturedby the detector. The pixel value generated by the detector may bereferred to as an output of the detector. By way of non-limitingexamples, each detector may be a photodetector, such as an avalanchephotodiode, an infrared photodetector, a quantum well infraredphotodetector, a microbolometer, or other detector capable of convertingEM radiation (e.g., of a certain wavelength) to a pixel value. The arrayof detectors may be arranged in rows and columns.

The detector output image may be, or may be considered, a data structurethat includes pixels and is a representation of the image dataassociated with the scene 1475, with each pixel having a pixel valuethat represents EM radiation emitted or reflected from a portion of thescene 1475 and received by a detector that generates the pixel value.Based on context, a pixel may refer to a detector of the image detectorcircuit 1465 that generates an associated pixel value or a pixel (e.g.,pixel location, pixel coordinate) of the detector output image formedfrom the generated pixel values. In one example, the detector outputimage may be an infrared image (e.g., thermal infrared image). For athermal infrared image (e.g., also referred to as a thermal image), eachpixel value of the thermal infrared image may represent a temperature ofa corresponding portion of the scene 1475. In another example, thedetector output image may be a visible-light image.

In an aspect, the pixel values generated by the image detector circuit1465 may be represented in terms of digital count values generated basedon the electrical signals obtained from converting the detectedradiation. For example, in a case that the image detector circuit 1465includes or is otherwise coupled to an ADC circuit, the ADC circuit maygenerate digital count values based on the electrical signals. In someembodiments, the ADC circuit may be a multi-ranging ADC circuit, such asa two-slope ADC circuit. For an ADC circuit that can represent anelectrical signal using 14 bits, the digital count value may range from0 to 16,383. In such cases, the pixel value of the detector may be thedigital count value output from the ADC circuit. In other cases (e.g.,in cases without an ADC circuit), the pixel value may be analog innature with a value that is, or is indicative of, the value of theelectrical signal. As an example, for infrared imaging, a larger amountof IR radiation being incident on and detected by the image detectorcircuit 1465 (e.g., an IR image detector circuit) is associated withhigher digital count values and higher temperatures.

The readout circuit 1470 may be utilized as an interface between theimage detector circuit 1465 that detects the image data and the logicdevice 1410 that processes the detected image data as read out by thereadout circuit 1470, with communication of data from the readoutcircuit 1470 to the logic device 1410 facilitated by the image interface1425. An image capturing frame rate may refer to the rate (e.g.,detector output images per second) at which images are detected/outputin a sequence by the image detector circuit 1465 and provided to thelogic device 1410 by the readout circuit 1470. The readout circuit 1470may read out the pixel values generated by the image detector circuit1465 in accordance with an integration time (e.g., also referred to asan integration period).

In various embodiments, a combination of the image detector circuit 1465and the readout circuit 1470 may be, may include, or may togetherprovide an FPA. In some aspects, the image detector circuit 1465 may bea thermal image detector circuit that includes an array ofmicrobolometers, and the combination of the image detector circuit 1465and the readout circuit 1470 may be referred to as a microbolometer FPA.In some cases, the array of microbolometers may be arranged in rows andcolumns. The microbolometers may detect IR radiation and generate pixelvalues based on the detected IR radiation. For example, in some cases,the microbolometers may be thermal IR detectors that detect IR radiationin the form of heat energy and generate pixel values based on the amountof heat energy detected. The microbolometers may absorb incident IRradiation and produce a corresponding change in temperature in themicrobolometers. The change in temperature is associated with acorresponding change in resistance of the microbolometers. With eachmicrobolometer functioning as a pixel, a two-dimensional image orpicture representation of the incident IR radiation can be generated bytranslating the changes in resistance of each microbolometer into atime-multiplexed electrical signal. The translation may be performed bythe ROIC. The microbolometer FPA may include IR detecting materials suchas amorphous silicon (a-Si), vanadium oxide (VO_(x)), a combinationthereof, and/or other detecting material(s). In an aspect, for amicrobolometer FPA, the integration time may be, or may be indicativeof, a time interval during which the microbolometers are biased. In thiscase, a longer integration time may be associated with higher gain ofthe IR signal, but not more IR radiation being collected. The IRradiation may be collected in the form of heat energy by themicrobolometers.

In some cases, the image capture component 1420 may include one or moreoptical components and/or one or more filters. The optical component(s)may include one or more windows, lenses, mirrors, beamsplitters, beamcouplers, and/or other components to direct and/or focus radiation tothe image detector circuit 1465. The optical component(s) may includecomponents each formed of material and appropriately arranged accordingto desired transmission characteristics, such as desired transmissionwavelengths and/or ray transfer matrix characteristics. The filter(s)may be adapted to pass radiation of some wavelengths but substantiallyblock radiation of other wavelengths. For example, the image capturecomponent 1420 may be an IR imaging device that includes one or morefilters adapted to pass IR radiation of some wavelengths whilesubstantially blocking IR radiation of other wavelengths (e.g., MWIRfilters, thermal IR filters, and narrow-band filters). In this example,such filters may be utilized to tailor the image capture component 1420for increased sensitivity to a desired band of IR wavelengths. In anaspect, an IR imaging device may be referred to as a thermal imagingdevice when the IR imaging device is tailored for capturing thermal IRimages. Other imaging devices, including IR imaging devices tailored forcapturing infrared IR images outside the thermal range, may be referredto as non-thermal imaging devices.

In one specific, not-limiting example, the image capture component 1420may include an IR imaging sensor having an FPA of detectors responsiveto IR radiation including near infrared (NIR), SWIR, MWIR, LWIR, and/orvery-long wave IR (VLWIR) radiation. In some other embodiments,alternatively or in addition, the image capture component 1420 mayinclude a complementary metal oxide semiconductor (CMOS) sensor or acharge-coupled device (CCD) sensor that can be found in any consumercamera (e.g., visible light camera).

In some embodiments, the imaging system 1400 includes a shutter 1485.The shutter 1485 may be operated to selectively inserted into an opticalpath between the scene 1475 and the image capture component 1420 toexpose or block the aperture 1480. In some cases, the shutter 1485 maybe moved (e.g., slid, rotated, etc.) manually (e.g., by a user of theimaging system 1400) and/or via an actuator (e.g., controllable by thelogic device 1410 in response to user input or autonomously, such as anautonomous decision by the logic device 1410 to perform a calibration ofthe imaging device 1405). When the shutter 1485 is outside of theoptical path to expose the aperture 1480, the electromagnetic radiationfrom the scene 1475 may be received by the image detector circuit 1465(e.g., via one or more optical components and/or one or more filters).As such, the image detector circuit 1465 captures images of the scene1475. The shutter 1485 may be referred to as being in an open positionor simply as being open. When the shutter 1485 is inserted into theoptical path to block the aperture 1480, the electromagnetic radiationfrom the scene 1475 is blocked from the image detector circuit 1465. Assuch, the image detector circuit 1465 captures images of the shutter1485. The shutter 1485 may be referred to as being in a closed positionor simply as being closed. In some cases, the shutter 1485 may block theaperture 1480 during a calibration process, in which the shutter 1485may be used as a uniform blackbody (e.g., a substantially uniformblackbody). For example, the shutter 1485 may be used as a singletemperature source or substantially single temperature source. In somecases, the shutter 1485 may be temperature controlled to provide atemperature controlled uniform blackbody (e.g., to present a uniformfield of radiation to the image detector circuit 1465). For example, insome cases, a surface of the shutter 1485 imaged by the image detectorcircuit 1465 may be implemented by a uniform blackbody coating. In somecases, such as for an imaging device without a shutter or with a brokenshutter or as an alternative to the shutter 1485, a case or holster ofthe imaging device 1405, a lens cap, a cover, a wall of a room, or othersuitable object/surface may be used to provide a uniform blackbody(e.g., substantially uniform blackbody) and/or a single temperaturesource (e.g., substantially single temperature source).

Other imaging sensors that may be embodied in the image capturecomponent 1420 include a photonic mixer device (PMD) imaging sensor orother time of flight (ToF) imaging sensor, LIDAR imaging device, RADARimaging device, millimeter imaging device, positron emission tomography(PET) scanner, single photon emission computed tomography (SPECT)scanner, ultrasonic imaging device, or other imaging devices operatingin particular modalities and/or spectra. It is noted that for some ofthese imaging sensors that are configured to capture images inparticular modalities and/or spectra (e.g., infrared spectrum, etc.),they are more prone to produce images with low frequency shading, forexample, when compared with a typical CMOS-based or CCD-based imagingsensors or other imaging sensors, imaging scanners, or imaging devicesof different modalities.

The images, or the digital image data corresponding to the images,provided by the image capture component 1420 may be associated withrespective image dimensions (also referred to as pixel dimensions). Animage dimension, or pixel dimension, generally refers to the number ofpixels in an image, which may be expressed, for example, in widthmultiplied by height for two-dimensional images or otherwise appropriatefor relevant dimension or shape of the image. Thus, images having anative resolution may be resized to a smaller size (e.g., having smallerpixel dimensions) in order to, for example, reduce the cost ofprocessing and analyzing the images. Filters (e.g., a non-uniformityestimate) may be generated based on an analysis of the resized images.The filters may then be resized to the native resolution and dimensionsof the images, before being applied to the images.

The image interface 1425 may include, in some embodiments, appropriateinput ports, connectors, switches, and/or circuitry configured tointerface with external devices (e.g., a remote device 1455 and/or otherdevices) to receive images (e.g., digital image data) generated by orotherwise stored at the external devices. In an aspect, the imageinterface 1425 may include a serial interface and telemetry line forproviding metadata associated with image data. The received images orimage data may be provided to the logic device 1410. In this regard, thereceived images or image data may be converted into signals or datasuitable for processing by the logic device 1410. For example, in oneembodiment, the image interface 1425 may be configured to receive analogvideo data and convert it into suitable digital data to be provided tothe logic device 1410.

The image interface 1425 may include various standard video ports, whichmay be connected to a video player, a video camera, or other devicescapable of generating standard video signals, and may convert thereceived video signals into digital video/image data suitable forprocessing by the logic device 1410. In some embodiments, the imageinterface 1425 may also be configured to interface with and receiveimages (e.g., image data) from the image capture component 1420. Inother embodiments, the image capture component 1420 may interfacedirectly with the logic device 1410.

The control component 1430 includes, in one embodiment, a user inputand/or an interface device, such as a rotatable knob (e.g.,potentiometer), push buttons, slide bar, keyboard, and/or other devices,that is adapted to generate a user input control signal. The logicdevice 1410 may be configured to sense control input signals from a uservia the control component 1430 and respond to any sensed control inputsignals received therefrom. The logic device 1410 may be configured tointerpret such a control input signal as a value, as generallyunderstood by one skilled in the art. In one embodiment, the controlcomponent 1430 may include a control unit (e.g., a wired or wirelesshandheld control unit) having push buttons adapted to interface with auser and receive user input control values. In one implementation, thepush buttons and/or other input mechanisms of the control unit may beused to control various functions of the imaging device 1405, such ascalibration initiation and/or related control, shutter control,autofocus, menu enable and selection, field of view, brightness,contrast, noise filtering, image enhancement, and/or various otherfeatures.

The display component 1435 includes, in one embodiment, an image displaydevice (e.g., a liquid crystal display (LCD)) or various other types ofgenerally known video displays or monitors. The logic device 1410 may beconfigured to display image data and information on the displaycomponent 1435. The logic device 1410 may be configured to retrieveimage data and information from the memory component 1415 and displayany retrieved image data and information on the display component 1435.The display component 1435 may include display circuitry, which may beutilized by the logic device 1410 to display image data and information.The display component 1435 may be adapted to receive image data andinformation directly from the image capture component 1420, logic device1410, and/or image interface 1425, or the image data and information maybe transferred from the memory component 1415 via the logic device 1410.In some aspects, the control component 1430 may be implemented as partof the display component 1435. For example, a touchscreen of the imagingdevice 1405 may provide both the control component 1430 (e.g., forreceiving user input via taps and/or other gestures) and the displaycomponent 1435 of the imaging device 1405.

The sensing component 1440 includes, in one embodiment, one or moresensors of various types, depending on the application or implementationrequirements, as would be understood by one skilled in the art. Sensorsof the sensing component 1440 provide data and/or information to atleast the logic device 1410. In one aspect, the logic device 1410 may beconfigured to communicate with the sensing component 1440. In variousimplementations, the sensing component 1440 may provide informationregarding environmental conditions, such as outside temperature,lighting conditions (e.g., day, night, dusk, and/or dawn), humiditylevel, specific weather conditions (e.g., sun, rain, and/or snow),distance (e.g., laser rangefinder or time-of-flight camera), and/orwhether a tunnel or other type of enclosure has been entered or exited.The sensing component 1440 may represent conventional sensors asgenerally known by one skilled in the art for monitoring variousconditions (e.g., environmental conditions) that may have an effect(e.g., on the image appearance) on the image data provided by the imagecapture component 1420.

In some implementations, the sensing component 1440 (e.g., one or moresensors) may include devices that relay information to the logic device1410 via wired and/or wireless communication. For example, the sensingcomponent 1440 may be adapted to receive information from a satellite,through a local broadcast (e.g., radio frequency (RF)) transmission,through a mobile or cellular network and/or through information beaconsin an infrastructure (e.g., a transportation or highway informationbeacon infrastructure), or various other wired and/or wirelesstechniques. In some embodiments, the logic device 1410 can use theinformation (e.g., sensing data) retrieved from the sensing component1440 to modify a configuration of the image capture component 1420(e.g., adjusting a light sensitivity level, adjusting a direction orangle of the image capture component 1420, adjusting an aperture, etc.).The sensing component 1440 may include a temperature sensing componentto provide temperature data (e.g., one or more measured temperaturevalues) various components of the imaging device 1405, such as the imagedetection circuit 1465 and/or the shutter 1485. By way of non-limitingexamples, a temperature sensor may include a thermistor, thermocouple,thermopile, pyrometer, and/or other appropriate sensor for providingtemperature data.

In some embodiments, various components of the imaging system 1400 maybe distributed and in communication with one another over a network1460. In this regard, the imaging device 1405 may include a networkinterface 1445 configured to facilitate wired and/or wirelesscommunication among various components of the imaging system 1400 overthe network 1460. In such embodiments, components may also be replicatedif desired for particular applications of the imaging system 1400. Thatis, components configured for same or similar operations may bedistributed over a network. Further, all or part of any one of thevarious components may be implemented using appropriate components ofthe remote device 1455 (e.g., a conventional digital video recorder(DVR), a computer configured for image processing, and/or other device)in communication with various components of the imaging system 1400 viathe network interface 1445 over the network 1460, if desired. Thus, forexample, all or part of the logic device 1410, all or part of the memorycomponent 1415, and/or all of part of the display component 1435 may beimplemented or replicated at the remote device 1455. In someembodiments, the imaging system 1400 may not include imaging sensors(e.g., image capture component 1420), but instead receive images orimage data from imaging sensors located separately and remotely from thelogic device 1410 and/or other components of the imaging system 1400. Itwill be appreciated that many other combinations of distributedimplementations of the imaging system 1400 are possible, withoutdeparting from the scope and spirit of the disclosure.

Furthermore, in various embodiments, various components of the imagingsystem 1400 may be combined and/or implemented or not, as desired ordepending on the application or requirements. In one example, the logicdevice 1410 may be combined with the memory component 1415, imagecapture component 1420, image interface 1425, display component 1435,sensing component 1440, and/or network interface 1445. In anotherexample, the logic device 1410 may be combined with the image capturecomponent 1420, such that certain functions of the logic device 1410 areperformed by circuitry (e.g., a processor, a microprocessor, a logicdevice, a microcontroller, etc.) within the image capture component1420.

FIG. 15 illustrates a block diagram of an example image sensor assembly1500 in accordance with one or more embodiments of the presentdisclosure. Not all of the depicted components may be required, however,and one or more embodiments may include additional components not shownin the figure. Variations in the arrangement and type of the componentsmay be made without departing from the spirit or scope of the claims asset forth herein. Additional components, different components, and/orfewer components may be provided. In an embodiment, the image sensorassembly 1500 may be an FPA, for example, implemented as the imagecapture component 1420 of FIG. 14 .

The image sensor assembly 1500 includes a unit cell array 1505, columnmultiplexers 1510 and 1515, column amplifiers 1520 and 1525, a rowmultiplexer 1530, control bias and timing circuitry 1535, adigital-to-analog converter (DAC) 1540, and a data output buffer 1545.In some aspects, operations of and/or pertaining to the unit cell array1505 and other components may be performed according to a system clockand/or synchronization signals (e.g., line synchronization (LSYNC)signals). The unit cell array 1505 includes an array of unit cells. Inan aspect, each unit cell may include a detector (e.g., a pixel) andinterface circuitry. The interface circuitry of each unit cell mayprovide an output signal, such as an output voltage or an outputcurrent, in response to a detection signal (e.g., detection current,detection voltage) provided by the detector of the unit cell. The outputsignal may be indicative of the magnitude of EM radiation received bythe detector and may be referred to as image pixel data or simply imagedata. The column multiplexer 1515, column amplifiers 1520, rowmultiplexer 1530, and data output buffer 1545 may be used to provide theoutput signals from the unit cell array 1505 as a data output signal ona data output line 1550. The output signals on the data output line 1550may be provided to components downstream of the image sensor assembly1500, such as processing circuitry (e.g., the logic device 1410 of FIG.14 ), memory (e.g., the memory component 1415 of FIG. 14 ), displaydevice (e.g., the display component 1435 of FIG. 14 ), and/or othercomponent to facilitate processing, storage, and/or display of theoutput signals. The data output signal may be an image formed of thepixel values for the image sensor assembly 1500. In this regard, thecolumn multiplexer 1515, the column amplifiers 1520, the row multiplexer1530, and the data output buffer 1545 may collectively provide an ROIC(or portion thereof) of the image sensor assembly 1500. In an aspect,the interface circuitry may be considered part of the ROIC, or may beconsidered an interface between the detectors and the ROIC. In someembodiments, components of the image sensor assembly 1500 may beimplemented such that the unit cell array 1505 and the ROIC may be partof a single die.

The column amplifiers 1525 may generally represent any column processingcircuitry as appropriate for a given application (analog and/ordigital), and is not limited to amplifier circuitry for analog signals.In this regard, the column amplifiers 1525 may more generally bereferred to as column processors in such an aspect. Signals received bythe column amplifiers 1525, such as analog signals on an analog busand/or digital signals on a digital bus, may be processed according tothe analog or digital nature of the signal. As an example, the columnamplifiers 1525 may include circuitry for processing digital signals. Asanother example, the column amplifiers 1525 may be a path (e.g., noprocessing) through which digital signals from the unit cell array 1505traverses to get to the column multiplexer 1515. As another example, thecolumn amplifiers 1525 may include an ADC for converting analog signalsto digital signals (e.g., to obtain digital count values). These digitalsignals may be provided to the column multiplexer 1515.

Each unit cell may receive a bias signal (e.g., bias voltage, biascurrent) to bias the detector of the unit cell to compensate fordifferent response characteristics of the unit cell attributable to, forexample, variations in temperature, manufacturing variances, and/orother factors. For example, the control bias and timing circuitry 1535may generate the bias signals and provide them to the unit cells. Byproviding appropriate bias signals to each unit cell, the unit cellarray 1505 may be effectively calibrated to provide accurate image datain response to light (e.g., visible-light, IR light) incident on thedetectors of the unit cells. In an aspect, the control bias and timingcircuitry 1535 may be, may include, or may be a part of, a logiccircuit.

The control bias and timing circuitry 1535 may generate control signalsfor addressing the unit cell array 1505 to allow access to and readoutof image data from an addressed portion of the unit cell array 1505. Theunit cell array 1505 may be addressed to access and readout image datafrom the unit cell array 1505 row by row, although in otherimplementations the unit cell array 1505 may be addressed column bycolumn or via other manners.

The control bias and timing circuitry 1535 may generate bias values andtiming control voltages. In some cases, the DAC 1540 may convert thebias values received as, or as part of, data input signal on a datainput signal line 1555 into bias signals (e.g., analog signals on analogsignal line(s) 1560) that may be provided to individual unit cellsthrough the operation of the column multiplexer 1510, column amplifiers1520, and row multiplexer 1530. For example, the DAC 1540 may drivedigital control signals (e.g., provided as bits) to appropriate analogsignal levels for the unit cells. In some technologies, a digitalcontrol signal of 0 or 1 may be driven to an appropriate logic lowvoltage level or an appropriate logic high voltage level, respectively.In another aspect, the control bias and timing circuitry 1535 maygenerate the bias signals (e.g., analog signals) and provide the biassignals to the unit cells without utilizing the DAC 1540. In thisregard, some implementations do not include the DAC 1540, data inputsignal line 1555, and/or analog signal line(s) 1560. In an embodiment,the control bias and timing circuitry 1535 may be, may include, may be apart of, or may otherwise be coupled to the logic device 1410 and/orimage capture component 1420 of FIG. 14 .

In an embodiment, the image sensor assembly 1500 may be implemented aspart of an imaging device (e.g., the imaging device 1405). In additionto the various components of the image sensor assembly 1500, the imagingdevice may also include one or more processors, memories, logic,displays, interfaces, optics (e.g., lenses, mirrors, beamsplitters),and/or other components as may be appropriate in variousimplementations. In an aspect, the data output signal on the data outputline 1550 may be provided to the processors (not shown) for furtherprocessing. For example, the data output signal may be an image formedof the pixel values from the unit cells of the image sensor assembly1500. The processors may perform operations such as non-uniformitycorrection (e.g., flat-field correction or other calibration technique),spatial and/or temporal filtering, and/or other operations. The images(e.g., processed images) may be stored in memory (e.g., external to orlocal to the imaging system) and/or displayed on a display device (e.g.,external to and/or integrated with the imaging system). The variouscomponents of FIG. 15 may be implemented on a single chip or multiplechips. Furthermore, while the various components are illustrated as aset of individual blocks, various of the blocks may be merged togetheror various blocks shown in FIG. 15 may be separated into separateblocks.

It is noted that in FIG. 15 the unit cell array 1505 is depicted as an8×8 (e.g., 8 rows and 8 columns of unit cells. However, the unit cellarray 1505 may be of other array sizes. By way of non-limiting examples,the unit cell array 1505 may include 160×120 (e.g., 160 rows and 120columns of unit cells), 512×512, 1024×1024, 2048×2048, 4096×4096,8192×8192, and/or other array sizes. In some cases, the array size mayhave a row size (e.g., number of detectors in a row) different from acolumn size (e.g., number of detectors in a column). Examples of framerates may include 30 Hz, 60 Hz, and 120 Hz. In an aspect, each unit cellof the unit cell array 205 may represent a pixel.

It is noted that dimensional aspects provided above are examples andthat other values for the dimensions can be utilized in accordance withone or more implementations. Furthermore, the dimensional aspectsprovided above are generally nominal values. As would be appreciated bya person skilled in the art, each dimensional aspect has a toleranceassociated with the dimensional aspect. Similarly, aspects related todistances between features also have associated tolerances.

FIG. 16 illustrates a perspective view of an additional imaging device1600 in accordance with one or more embodiments of the presentdisclosure. Except as otherwise described below, the imaging device 1600may be similar to imaging device 100, imaging device 200, imaging device800, and/or imaging device 1405, described above. In addition, imagingdevice 1600 may be manufactured using various steps of process 900,described above. Imaging device 1600 may also be used using varioussteps of process 1100, described above.

For example, imaging device 1600 uses a triplet lens configuration, witha first lens element 1610, a second lens element 1612, and a third lenselement 1614. First lens element 1610 may be similar to any of lenselement 335, lens element 1235, lens element 1240, or lens element 1335,described above. Second lens element 1612 may be similar to any of lenselement 340, lens element 1245, lens element 1340, or lens element 1345,described above. Third lens element 1614 may be similar to any of lenselement 345, lens element 1250, lens element 1345, or lens element 1350,described above. First lens element 1610 may be an AB lens, and secondand third lens elements 1612, 1614 may be EF and IJ lenses, althoughother configurations are contemplated. First lens element 1610 may bereferred to as the upper lens of imaging device 1600. The lower twolenses (i.e., second lens element 1612 and third lens element 1614),which may be referred to as “the doublet” collectively, may be able toimage independently of the upper lens.

As shown, imaging device 1600 includes a lens barrel 1618. Lens barrel1618 includes a first body portion 1620 and a second body portion 1622.First body portion 1620 may be referred to as a barrel, a first lensbarrel component, an upper lens assembly, or a top portion of lensbarrel 1618. The first lens element 1610 may be at least partiallydisposed in first body portion 1620. In embodiments, first lens element1610 may include a first lens group of first body portion 1620 and/orlens barrel 1618. First body portion 1620 may have a conical shape witha groove or rim 1624 to receive first lens element 1610, although otherconfigurations are contemplated. First body portion 1620 may be similarto body portion 815, described above.

Second body portion 1622 may be referred to as a doublet, a second lensbarrel component, a lower lens assembly, or a bottom portion of lensbarrel 1618. The second lens element 1612 and third lens element 1614may be at least partially disposed in second body portion 1622. Inembodiments, second and third lens elements 1612, 1614 may include asecond lens group of second body portion 1622 and/or lens barrel 1618.As shown, a spacer element 1630 may be positioned, or otherwise defined,in second body portion 1622 to position second lens element 1612 andthird lens element 1614 in second body portion 1622 (e.g., to define aproper spacing between second lens element 1612 and third lens element1614, to secure second lens element 1612 and third lens element 1614 insecond body portion 1622, etc.). In embodiments, second body portion1622 may be attached to a housing of imaging device 1600, such ashousing 810 described above. For example, second body portion 1622 mayinclude external threads 1632 for threading second body portion 1622 tohousing 810. Second body portion 1622 may be similar to body portion820, described above.

First body portion 1620 can be detached from the second body portion1622, such as via a quick attachment mechanism, as detailed below. Inthis manner, first body portion 1620 can be removed from second bodyportion 1622, such as to facilitate replacement of first body portion1620 and/or second body portion 1622, testing of imaging device 1600,manufacturing of imaging device 1600, etc., and easily reattached. Forexample, it may be convenient to test the whole imaging device 1600(including the first body portion 1620) after assembly, but only use thebottom two lenses (“doublet configuration”) during the camera housingattachment and camera focus processes. The first body portion 1620 canthen be reattached for further steps, such as calibration, for instance.

FIG. 17 illustrates a cross-sectional view of first body portion 1620 inaccordance with one or more embodiments of the present disclosure. FIG.18 illustrates a cross-sectional view of second body portion 1622 inaccordance with one or more embodiments of the present disclosure.Referring to FIGS. 16-18 , imaging device 1600 includes a snap-fitmechanism 1650 releasably securing first body portion 1620 to secondbody portion 1622. In this manner, first body portion 1620 and secondbody portion 1622 are designed to snap together using a snap-fit.Although a snap-fit is shown and described, first body portion 1620 andsecond body portion 1622 can be releasably secured together using otherquick-attachment mechanisms and devices. Suitable mechanisms/devicesinclude those that allow first body portion 1620 to be connected to andremoved from second body portion 1622 without damage or loss of functionof the quick-attachment mechanism/device.

As shown, first body portion 1620 includes one or more finger members1652 (e.g., a plurality of finger members 1652, such as two fingermembers 1652, for instance) that fit into complementary notches 1654 insecond body portion 1622. In embodiments, the snap-fit mechanism 1650may be designed to reversible, meaning the snap-fit mechanism 1650 canbe disconnected without damage. For example, the tips of the fingermembers 1652 may have a bevel on the leading and trailing edges allowingthe reversible, bi-directional behavior. The notches 1654 may includecorresponding structure facilitating the reversible, bi-directionalbehavior. In this manner, finger members 1652 and/or notches 1654 mayinclude a bevel facilitating removal of the finger members 1652 from thenotches 1654 without damage.

In embodiments, the finger members 1652 and notches 1654 may bepositioned to facilitate proper alignment of first body portion 1620 andsecond body portion 1622. For example, finger members 1652 and notches1654 may align first body portion 1620 and second body portion 1622co-axially, rotationally, or the like. For instance, finger members 1652and notches 1654 may be arranged to fix a rotational position of firstbody portion 1620 relative to second body portion 1622, such as limitingrotation of first body portion 1620 relative to second body portion 1622about a co-axial axis. In embodiments, second body portion 1622 mayinclude one or more flanges 1660 positioned adjacent to finger members1652 to limit rotation of first body portion 1620 relative to secondbody portion 1622.

FIG. 19 illustrates a flow diagram of an example process 1900 formanufacturing imaging device 1600 in accordance with one or moreembodiments of the disclosure. For explanatory purposes, the exampleprocess 1900 is described herein with reference to components of FIGS.16-18 . FIGS. 16-18 illustrate perspective views associated withmanufacturing the imaging device 1600. However, the example process 1900is not limited to the components of FIGS. 16-18 .

In block 1910, process 1900 includes providing lens barrel 1618including first body portion 1620, second body portion 1622, andsnap-fit mechanism 1650. First body portion 1620 includes first lenselement 1610 at least partially disposed therein. Second body portion1622 includes second lens element 1612 and third lens element 1614 atleast partially disposed therein. First, second, and third lens elements1610, 1612, 1614 include a lens system configured to passelectromagnetic radiation from a scene to an image capture component(e.g., image capture component 1420). Snap-fit mechanism 1650 mayinclude a plurality of finger members 1652 extended from first bodyportion 1620 and a plurality of complementary notches 1654 in secondbody portion 1622. Block 1910 may include disposing first lens element1610 within first body portion 1620. Block 1910 may include disposingsecond and third lens elements 1612, 1614 within second body portion1622.

In block 1920, process 1900 includes securing first body portion 1620 tosecond body portion 1622 using snap-fit mechanism 1650. Finger members1652 may be configured to engage with the notches 1654 to releasablysecure first body portion 1620 to second body portion 1622. Block 1920may include arranging the finger members 1652 and notches 1654 to fix arotational position of first body portion 1620 relative to second bodyportion 1622, such as to limit rotation of first body portion 1620relative to second body portion 1622 about a co-axial axis.

In block 1930, process 1900 may include disconnecting snap-fit mechanism1650 to separate first body portion 1620 from second body portion 1622.

In block 1940, process 1900 may include performing first manufacturingoperations when first body portion 1620 and second body portion 1622 areseparated. For example, the first manufacturing operations may includeone or more calibration tests of second and third lens elements 1612,1614, such as a focus process or any other processes/tests describedherein. In embodiments, the first manufacturing operations may includeconnecting second body portion 1622 to a housing (e.g., housing 810).

In block 1950, process 1900 may include reconnecting first body portion1620 to second body portion 1622 using snap-fit mechanism 1650. Forexample, first body portion 1620 may be positioned to second bodyportion 1622 and finger members 1652 snapped into notches 1654.

In block 1960, process 1900 may include performing second manufacturingoperations when first body portion 1620 and second body portion 1622 areconnected. For example, the second manufacturing operations may includeone or more calibration tests of the lens system, the complete lensbarrel, or the like.

Where applicable, various embodiments provided by the present disclosurecan be implemented using hardware, software, or combinations of hardwareand software. Also where applicable, the various hardware componentsand/or software components set forth herein can be combined intocomposite components comprising software, hardware, and/or both withoutdeparting from the spirit of the present disclosure. Where applicable,the various hardware components and/or software components set forthherein can be separated into sub-components comprising software,hardware, or both without departing from the spirit of the presentdisclosure. In addition, where applicable, it is contemplated thatsoftware components can be implemented as hardware components, and viceversa.

Software in accordance with the present disclosure, such asnon-transitory instructions, program code, and/or data, can be stored onone or more non-transitory machine readable mediums. It is alsocontemplated that software identified herein can be implemented usingone or more general purpose or specific purpose computers and/orcomputer systems, networked and/or otherwise. Where applicable, theordering of various steps described herein can be changed, combined intocomposite steps, and/or separated into sub-steps to provide featuresdescribed herein.

The foregoing description is not intended to limit the presentdisclosure to the precise forms or particular fields of use disclosed.Embodiments described above illustrate but do not limit the invention.It is contemplated that various alternate embodiments and/ormodifications to the present invention, whether explicitly described orimplied herein, are possible in light of the disclosure. Accordingly,the scope of the invention is defined only by the following claims.

What is claimed is:
 1. An imaging device comprising: a lens barrel comprising: first body portion comprising a first lens element at least partially disposed therein; a second body portion comprising a second lens element and a third lens element at least partially disposed therein, wherein the first, second, and third lens elements comprise a lens system configured to pass electromagnetic radiation from a scene to an image capture component; and a snap-fit mechanism comprising a plurality of finger members extended from the first body portion and a plurality of complementary notches in the second body portion, wherein the finger members are configured to engage with the notches to releasably secure the first body portion to the second body portion.
 2. The imaging device of claim 1, wherein the one or more finger members and/or the notches comprise a bevel that facilitates removal of the one or more finger members from the notches.
 3. The imaging device of claim 1, wherein the finger members and the notches are arranged to fix a rotational position of the first body portion relative to the second body portion.
 4. The imaging device of claim 3, wherein the second body portion comprises one or more flanges positioned adjacent to the finger members to limit rotation of the first body portion relative to the second body portion.
 5. The imaging device of claim 1, further comprising a spacer positioned or otherwise defined in the second body portion to position the second lens element and the third lens element in the second body portion.
 6. The imaging device of claim 1, further comprising a housing, wherein the second body portion comprises external threads for threading the second body portion to the housing.
 7. The imaging device of claim 1, wherein: the first lens element comprises a first lens group; and the first lens element is a spherical lens element configured to transmit electromagnetic radiation associated with the scene.
 8. The imaging device of claim 7, wherein: the second lens element and the third lens element comprise a second lens group; and the second and third lens elements are wafer level optics (WLO) aspherical lens elements configured to receive the electromagnetic radiation from the first lens group and transmit the electromagnetic radiation.
 9. The imaging device of claim 8, wherein: the first lens group is associated with a first field of view; and the second lens group is associated with a second field of view narrower than the first field of view.
 10. The imaging device of claim 1, wherein the image capture component comprises a detector array comprising a plurality of detectors, wherein each of the plurality of detectors is configured to receive a portion of the electromagnetic radiation and generate a thermal image based on the electromagnetic radiation.
 11. A method of manufacturing the imaging device of claim 1, the method comprising: disposing the first lens element at least partially within the first body portion; disposing the second lens element and the third lens element at least partially within the second body portion; coupling the second body portion to a housing; performing a calibration of the second lens element and the third lens element; and after the calibration, coupling the first body portion to the second body portion.
 12. A method of manufacturing the imaging device of claim 1, the method comprising: performing a first manufacturing operation when the first body portion and the second body portion are connected; disconnecting the snap-fit mechanism to separate the first body portion from the second body portion; and performing a second manufacturing operation when the first body portion is separated from the second body portion.
 13. The method of claim 12, wherein: the first manufacturing operation comprises one or more first calibration tests of the lens system; and the second manufacturing operation comprises one or more second calibration tests of the second and third lens elements.
 14. The method of claim 13, wherein the one or more second calibration tests comprise a focus process.
 15. A method comprising: providing a lens barrel, the lens barrel comprising: a first body portion comprising a first lens element at least partially disposed therein, and a second body portion comprising a second lens element and a third lens element at least partially disposed therein, wherein the first, second, and third lens elements comprise a lens system configured to pass electromagnetic radiation from a scene to an image capture component, and a snap-fit mechanism comprising a plurality of finger members extended from the first body portion and a plurality of complementary notches in the second body portion; and securing the first body portion to the second body portion using the snap-fit mechanism, wherein the finger members are configured to engage with the notches to releasably secure the first body portion to the second body portion.
 16. The method of claim 15, wherein the securing comprises arranging the finger members and the notches to fix a rotational position of the first body portion relative to the second body portion.
 17. The method of claim 15, further comprising: disconnecting the snap-fit mechanism to separate the first body portion from the second body portion; and reconnecting the first body portion to the second body portion using the snap-fit mechanism.
 18. The method of claim 17, further comprising performing a first manufacturing operation when the first body portion is separated from the second body portion.
 19. The method of claim 18, further comprising performing a second manufacturing operation when the first and second body portions are reconnected.
 20. The method of claim 19, wherein each of the first manufacturing operation and the second manufacturing operation comprises one or more calibration tests. 